Power plant speed and temperature control



Sept. l, 1959 F. c. REGGIO 2,901,835

POWER PLANT SPEED AND TEMPERATURE CONTROL Original Filed Dec. 15,' 1941E 2 Sheets-Sheet 1 Sept. l, 1959 Original Filed Dec. 15, 1941 F. c.REGGIO 2,901,885

POWER PLANT SPEED AND TEMPERTURE CONTROL 2 Sheets-Sheet 2 United StatesPatent POWER PLANT SPEED AND TEMPERATURE CONTROL Ferdinando CarloReggio, Norwalk, Conn.

Original application December 15, 1941, Serial No. 423,001. Divided andthis application April 25, 1955, Serial No. `503,576

* Claims. (Cl. 6G-13) This invention relates to improved engineregulating devices and has particular reference to power controlapparatus for automotive and aircraft powerplants.

The present application is a division of my copending application SerialNo. 423,001, filed December 15, 1941, now abandoned.

An object of the invention resides in the provision of a regulatingdevice for automatically varying the engine power output substantiallyas a preselected function of one or more engine operating conditions orother conditions affecting engine operation.

Another object is to provide a regulating device for automaticallylimiting the maximum engine output to a value depending on at least onevariable condition affecting engine operation such as an engineoperative temperature.

A further object is to provide a device for regulating the engine poweroutput by automatically varying the engine induction or manifoldpressure or the engine torque in dependence on preselected engineoperating conditions and the adjustment of a manual control member.

An additional object is to provide an improved device for regulating theengine either directly from a manually adjustable control member orautomatically in dependence on preselected variables.

A still further object is to provide an improved regulator forsupercharged engines having a variable-speed supercharger, such forexample as a supercharger driven by an exhaust gas turbine, forcontrolling the supercharger speed to vary the engine power outputsubstantially as a predetermined function of preselected variables.

Other objects and advantages will be more particularly pointed outhereinafter or will become apparent as the description proceeds. I

The drawings, in which there are diagrammatically illustrated suitableconstluctional arrangements for the purpose of disclosing the invention,are for purpose of illustration only and are not to be taken as limitingor restricting the scope of the invention.

In the drawings:

Fig. 1 is a sectional View of au engine regulato according to theinvention and includes in reduced scale a diagrammatic illustration ofan aircraft engine and control instrumentalities therefor.

Fig. 2 is a fragmentary modification of Fig. l.

Fig. 3 diagrammatically indicates a conventional variable-pitchpropeller driven by the engine of Fig. 1. Fig. 4 is an example of enginecalibration curve.

The characteristic power calibration curves of an aircraft engine,represented in Fig. 4, are referred to the axes of abscissae OX andordinates OY representing the engine manifold temperature and theindicated mean effective pressure respectively. The values of saidtemperature and pressure increase in the directions indicated by thearrows.

The four curves of Fig. 4 represent the result of Patented Sept. 1, 1959actual engine tests conducted with a specified fuel, 'at a given valueof engine speed and exhaust pressure. The curve A represents the engineindicated, mean effective pressure developed under a constant value ofmanifold pressure for different values of manifold temperature. Theslope of this curve shows a reduc- 'tion of indicated M.E.P. withincrease in manifold temperature, which is due mainly to thecorresponding reduction of density in the induction manifold. Curves Band C similarly indicate the indicated M.E.P., developed for twodifferent lower constant values of manifold pressure. The dotted line Lrepresents the upper limit for continuous operation, from which it isapparent that the maximum admissible value of the manifold pressure, andin turn of the indicated M.E.P., diminishes with an increase of manifoldtemperature.

In highly supercharged aircraft engines in which said temperature mayvary within wide limits, engine regulators for limiting the maximumengine torque or manifold pressure at a constant value have thedisadvantage that they either limit the engine output at anunnecessarily low value at low manifold temperature, or overload theengine at elevated temperature, or both. Accordingly, one of the objectsof the present invention is to provide a device for limiting the maximumengine output, or torque, or manifold pressure, to a value varyingsubstantially as a preselected function of the manifold temperature.

Furthermore, the upper limit for continuous operation varies uponchanges of fuel characteristics and other engine operative conditionssuch as exhaust pressure, cylinder temperature, engine speed,surrounding atmospheric conditions. Thus a further object of theinvention is to provide a regulator for varying the engine output, orthe manifold pressure, or the engine torque, upon variation of one ormore preselected variables such as the above.

While the curve L represents the upper limit for continuous operation,other similar curves may be determined corresponding to a maximum safetemporary engine overload, such as the upper limit for take-off power,which is also generally found to be dependent upon engine operativeconditions such as manifold temperature, exhaust pressure, etc.Accordingly still another object is to provide a regulating device asoutlined above, including a control member for selectively limiting themaximum engine output either at a safe value for continuous operation,or at a higher temporary value also variable upon changes of preselectedvariables. Furthermore the regulating device may be employed forautomatically adjusting the engine torque, or output, or the manifoldpressure, at values lower than those corresponding to the upper limitfor continuous operation, as will be apparent from the followingdescription.

One form of the invention is illustrated in Fig. 1 in combination withan engine such as an aircraft radial spark-ignition engine, although theinvention is in no way limited in its application to any particular formor type of engine. Such engine 6 has cylinders 7 receiving air orcombustible mixture from a blower or supercharger 8 by way of pipes ormanifold 9 forming part of the engine induction system. Liquid fuel maybe delivered to the engine by means of a carburetor or injection system,neither of which is shown in Fig. l. The supercharger 8 is driven atvariable speed by an exhaust gas turbine 10 connected by exhaust `pipe11 to the cylinder exhaust ports. The flow of exhaust gases to theturbine nozzles is regulated by a valve or blast gate 12. When thelatter is rotated clockwise by means of an actuating lever 114 allexhaust gases from lthe engine will be delivered to the turbine, whilewhen he valve 12 is rotated counter-clockwise the exhaust gases,discharge` through duct and the turbine becomes inoperative. Atintermediate positions of the valve 12 more or less exhaustv gasesy willbe supplied toV the turbine. A control member- 16 is connected withlever 14 by way of rod 17,'lever 18 and rod-19 and may be'employed todirectlyf control the adjustment of valve 12 and in turn the speed ofsupercharger 8 and the pressure of the air or combustible mixturedelivered to the engine cylinders by way of pipe or manifold 9,hereinafter referred to as manifold pressure or supercharged fluidpressure.

The engine 6 may drive a variable pitch propeler provided with aservo-motor such as a hydraulicor electric motor controlled by anengine-driven speed governor adjustable by means of lever 20, rod 21 andcontrol member 22,.for controlling said pitch thereof to automaticallykeep the engine speed constant at a value termined by the adjustment ofmember 22. in the arrangementidiagrammatically indicated in Fig. 3 eachof the propeller blades 95 is rotatable about a spider arm 96 attachedto ther propeller shaft 97. The latter has an internal chamber 98 closedbya cap 99 axially slidable on shaft 97 under hydraulic pressuresupplied to the chamber 98 by way of pipe 102.V The cap 99 has studs 100which engage slots in lugs 101 carried by the blades 95'. When thepropeller is in operation centrifugal and aerodynamic forces tend toturn the blades 95 into maximum pitch against hydraulic pressure.

A piston valve 104 controls the admission of lubrieating oil underpressure from a source, not shown, through pipes 105 and 102 to thechamber 98 and the discharge of oil from the latter through pipe 102`and an oil'return pipe 106 back to the engine. AThe piston valve 104 isactuated by the centrifugal force of the enginedriven flyweights 107acting against the load of spring 108 adjusted by means of lever 109keyed to the shaft of lever 20.'

Under steady ying conditions the yweights 107 are held in equilibrium bythe load of the spring 108 acting against the centrifugal force,variations in engine speed causing adjustment of the valve 104 and thuseffecting changes of propeller pitch tending to maintain the cnginespeed substantially constant at a value corresponding to `the adjustmentof the governor spring 108. The speed at which the governor willautomatically hold the engine may be changed by varying the angularadjustment of the Speed control lever 22 connected with lever 20,thereby altering the tension of Ithe governor spring 108. The abovedescribed mechanism including the variable-pitch propeller 95,.`t hehydraulically actuated slidable cap 99 for regulating said pitch thereofand the pilot valve 104 actuated by resiliently-loaded, enginedrivenyballs 107 for controlling said slidable cap is Y well known in the artand is per se no part of the presen t invention.

Two temperature responsive elements 24 and 25, the former connected tothe manifold 9 and responsive to the temperature of the air orcombustible mixture therein, hereinafter referred to as manifoldtemperature or supercharged fluid temperature, and the latter responsiveto the temperature of the engine cylinder, or suitable part associatedtherewith, or the coolant tenflperature, in a liquid cooledk engine, areconnected Iby way of rods to the ends of lever 26 rotatably carried atan intermediate point thereof by a bell-crank lever 27 for actuating alink or rod 28. An increase of temperature of either element rotateslever 27 clock-wise.

The engine regulating device, generally indicated at 29., mayconveniently comprise, a casing 30 having two pirlllell cylindricalbores therein. Within one of said boresthere is disposed. a reciprocablepiston 31 attached 10, 32 rotatably connected with lever 18 at anintermediate point thereof. I n the other bore there are mounted valveelements such as a reciprocable sleeve 34 provided with an axialcylindrical bore` in which there is slidably disposed a plunger valve 35having two spaced cylindrical discs 36 and 37 for controlling ports 38and 39 which are formed in sleeve 34 and so arranged as to be inpermanent ow communication by way of annular grooves formed in sleeve 34and ducts 40 and 41 respectively, with the piston cylinder on eitherside of piston 31.

The annular chamber between discs 36 and 37 is connected by way ofsuitable ports and line 43 with a source of pressure fluid, usually oilfrom the engine pressure lubricating system, While the two portions ofthe sleeve bore external to discs 36 and 37 are intercommunicating byway of conduits 44 and 4S, and are maintained at relatively 10W pressurethrough return line 46 leading oil back to a reservoir or engine sump.The above outlined hydraulic servo-motor is a known device, and it willbe readily understood that with the valve elements in relative neutraladjustments, with ports 38 and 39v closed, as shown in Fig. l, thepiston 31 is maintained stationary. Either a displacement toward ytheright of plunger valve 35 or a movement to the left of sleeve 34 causesthe cylinder chamber to the left of piston 31 to vbe connected with theoil return line 46, While oil under pressure is admitted to the otherside of the piston, thus displacing the same to the left and determiningclockwise rotation of lever 18 about its upper connection andcounter-clockwise rotation of valve 12. Opposite rotation of valve 12 isobviously determ-ined by displacement of plunger valve 35 toward theleft or movement of sleeve 34 to the right.

The left end of plunger valve 35 is connected with a lever 48 at anintermediate point thereof, while the lower end of said lever isprovided with a pin 49 cooperating with a slot 50 formed in disc 51keyed on a shaft carrying lever 52, which is connected with the rod 28actuated by bell crank lever 27. Thus the adjustment of the lower end oflever 48 varies 'as a function of the temperature of elements 24 and 25,said function depending upon the configuration of slot 50. The upper endof lever 48 is actuated by a member 54 secured to the movable walls oftwo diaphragm chambers or bellows 55 and 56. The former bellows isysecured to the cover 53 of housing 30, and the pressure in said bellowsis kept by way of pipe S7 at the same value as in the engine manifold 9,while bellows 56, provided with a calibrated spring 59 tending to expandthe same, is positioned by a member 58 slidably mounted in the wall ofhousing 30. A lever 60, rotatably carried at an intermediate pointthereof by member 58, is connected at its lower and upper ends with anadjusting member 61 and, by means of rod 62, with a manually adjustablemember 63, respectively.

The adjustment of the upper end of lever 48 is thus dependent on theadjustment of member 63 and the engine manifold pressure. If the areasof bellows 55 and 56 are equal, changes of pressure within the housing30 do not affect the adjustment of lever 48, the same being thusresponsive to the absolute manifold pressure. But if one of said bellowshas a larger area than the other, as shown for instance in Fig. 2, thenan increase of pressure within the housing 30 will tend to contract saidlarger bellows, thus displacing lever 48. Moreover, if bellows 56 is nothighly evacuated, butl contains a substantial mass of expansible fluid,the adjustment of lever 48 will also beY affected by changes oftemperature within housing 30. The control member 63 may be providedwith notches cooperating with a resiliently loaded detent 64. Fournotches, 131 toV 134, are indicated in l.

The sleeve 34 is `actuated by lever 65, which is connected at one endthereof with a rod 66 terminating in pin 67 cooperating with a slot 68formed in speed control member 22, whereby the ladjustment of sleeve 34is dependent on the engine speed. The other end of the same levercarries a pin 70 cooperating with a slot 71 formed in rod 72 slidablymounted in `a bore of housing 73 and connected with evacuated,resiliently loaded bellows 74 supported by adjustable member 75 carriedby the housing cover 76 which closes the bellows chamber. 'I he latteris maintained at exhaust pressure by means of pipe 77 connected with theengine exhaust pipe 11. Thus a change of exhaust pressure determines acorresponding displacement of the sleeve 34 dependent on the form of theslot 71.

The operation of the regulating device may be substantially `as follows:assuming the control member 63 to be set at maximum power for continuousoperation, with the detent 64 engaging the notch 132, control lever 16in full open adjustment, and lever 22 set for the desired value ofengine speed, the valve 12, as shown in Fig. l, is controlled by thehydraulic servo motor to maintain the engine manifold pressure at `acertain value depending on engine operative conditions as will presentlybe pointed out. A variation of manifold pressure, for example a dropthereof, determines contraction of bellows 55 and displacement ofplunger valve 35 to the left, thus setting piston 31 in motion to rotatevalve 12 clockwise and increase the speed of blower 8 and the manifoldpressure until the initial value thereof is restored, whereupon bellows55 resumes its initial position and returns plunger valve 35 to neutraladjustment relative to sleeve 34. If now the manifold temperature, orthe cylinder temperature, or both vary, for instance increase,determining counterclockwise rotation of disc 51, the lower end of lever48 and plunger valve 35 will be displaced to the right, causingcounterclockwise rotation of valve 12 to reduce the supercharger speedand the manifold pressure until bellows 55 has collapsed the necessaryamount to bring plunger valve 35 back to neutral position. A lowermanifold pressure is thus obtained corresponding to the higher manifoldand cylinder temperature; and the form of the slot 50 may be sodetermined that the manifold pressure varies with the manifoldtemperature substantially as indicated by curve L of Fig. 4. Similarly,either a variation of exhaust pressure causing expansion or contractionof bellows 74, axial displacement of rod 72 and correspondingdisplacement of upper end of lever 65, or a change in the adjustment ofspeed control lever 22 causing a corresponding displacement of the lowerend of same lever, produce an axial displacement of sleeve 34 which setspiston 31 in motion to vary the manifold pressure until bellows 55 hasexpanded or contracted to the extent of bringing plunger 35 again toneutral adjustment relative to sleeve 34 in the new position of thelatter. It is therefore clear that the manifold pressure is caused tovary fas a predetermined function of manifold and cylinder or otherengine operative temperature, exhaust pressure and engine speed, saidfunction obviously depending upon the form of slots 50, 71 and 68, orcams or other equivalent devices which may be substituted for saidslots.

As already stated, if bellows 55 and 56 have different eiective areas,and if .bellows 56 contains a substantial mass of gas, the manifoldpressure becomes also dependent on the pressure and temperature withinhousing 30, which may be substantially the same as the surroundingatmospheric pressure and temperature.

The above automatic regulation occurs when control lever 16 is in fullyopen adjustment, but at any time the pilot may rotate said leverclockwise for directly actuating valve 12 to reduce the manifoldpressure, and as long as the latter is below the maximum preselectedvalue corresponding to automatic operation, bellows 55 remainscontracted, with plunger 35 to the left of its neutral position andpiston 31 stationary in its extreme right position, the adjustment ofvalve 12 being thus determined by the adjustment of control lever 16.The regulating device however stands ready to resume control themanifold pressure attains said maximum predetermined value.

A displacement of control member 63, for example toward the left,determines a compression of bellows spring 59 or otherwise resilientlyloaded bellows 56 and corresponding contraction of bellows 55 causingthe valve 12 to be rotated clockwise to increase the manifold pressurevuntil bellows 55 again expands the amount necessary to bring the plungervalve 35 back to neutral position. The regulating devicefwill thusmaintain the manifold pressure, or the engine indicated M.E.1"., athigher values, which may be represented in Fig. 4 by a linesubstantially similar to curve L butl higher than the latter. In theexample shownin Fig. 1 the control member 63, which actuates lever 60 bymeans of rod '62, is provided With four notches 131,132, 133 and 134arranged to cooperate with the resilient detent 64. The adjustmentillustrated, with notch 132 engaged by the detent, may correspond tomaximum manifold pressure for continuous operation, while with notch134, 133 or 131 engaged by the detent the engine manifold pressure maybe automatically regulated for maximum take-off power (admissible forvery short time), or temporary overload such as may be required forrapid climbing to high altitude, or cruising power, respectively. Theforegoing assumes, of course, that control lever 16 is in fully openadjustment, and that the speed control member 22 is suitably set. For a`given adjustment of control member 63 the engine power output may becontrolled by varying the engine speed, through member 22. Furthermore,the portions of the connections between the various elements of theregulating device, such as slots 50, 71 and 68, which are effectiveduring cruising operation, may be so designed as to automaticallymaintainthe engine manifold pressure at values corresponding to maximumfuel economy.

Fuels of higher anti-knock rating have curves of maximum power forcontinuous output which are higher than.

ticular mechanical embodiments have been somewhat diagrammaticallyillustrated, the invention is not limited thereto. devices according tothe present invention may be used in connection with other types ofengine, such for example as compression-ignition or diesel engines, inwhich case they obviously will be operatively connected with fuelcontrol means such as the control member of the fuel injection pump, forregulating the engine supply of liquid fuel, or limiting the maximumamount of such supply, in dependence upon preselected operativeconditions.

Moreover, it is to be expressly understood that the invention may` beused in various ways, and that various modifications, substitutions,additions and omissions may be resorted to in the character,construction, arrangement and manner of operation and number of thevarious elements and parts Within the limits or scope of the inventionas dened in the appended claims.

In interpreting said claims, where they are directed to less than all ofthe elements of the complete system disclosed, they are to be construedas covering possible uses of the recited elements in installations whichlack the non-recited elements.

I claim:

l. In a speed and temperature control system for use with an internalcombustion engine having in series flow relation an air compressor, acombustion chamber and a gas turbine connected to drive said compressor;and including a power member driven by said engine under variable speedand load conditions; the combination comprising irst regulating meansresponsive to the speed of said power member for controlling the loadapplied thereto, second regulating means responsive to an oper.

ating temperature of the engine resulting from combustion It will bereadily understood that regulatingV tion oi v'said' atmosphericpressure. and surrounding;y

temperature.

2, In. a speedy and temperature control system vfor` use withan internalcombustion powerplanthavinga member driven by the powerplant` undervvariable speed and load conditions .and including in series flowrelation an ainfcompressor, a combustionicharmber and: a: gas turbineconnected to drive said compressor, the combination comrst regulatingmeansy responsive to the speed of saidmember for controlling the loadapplied thereto, second regulating.Y means responsive to an engineopertemperature resulting`` from combustion for controlling the supplyof actuating gas to` said turbine, means for changingthe datum of saidrst andv second regulating-vmeans, al control lever for operating saiddatum means to select various values of said temperaturel and speed, andambient temperature responsive means and means responsive to thepressure on` the dischargepside of said compressor operatively connectedtol saidsecond. regulating meansl to alter the operationy thereof as apreselected function of` said ambient temperature mid compressordischarge pressure.

3. In a speed and temperature control system for use with an internalcombustion powerplant havinga membei driven: by the powerplant undervariable speed and load conditions and including in series flow relationan air intake system with. a compressor therein,` a combustion chamberand a gasv discharge system with a turbine therein connected todri-veysaid compresson, the combination comprising first regulating meansresponsive to. the speed of said member for controlling the load appliedto said memberto regulate the speed thereof, secondregulating includingmeans responsive` to an operating temp eralure of the power-plantresulting from combustion for controlling the ratel of supply ofactuating gasy to said to4 regulate said temperature, means, forchanging the datum of said rst and second; regulating means, a controllever for operatingl said datum changing means to select; various,values of saidv speed and temperature, andfmansresponsive. to the`pressure in said gas discharge. system upstream from said gas turbineand means responsive. to. variations of the surroundingbarometricpressure for, altering the datum of the. second,Y regulating means to`vary the selectedv temperature independently of Said control lever.

4. Ink1 apparatus for. controlling the speed and temperature ofaninternal combustion powerplant driving a variable, pitch. propellerand including in series flow relation an,aircompressor, a combustionchamber and a gas turbine connected.v to drive said compressor at speedindependent of the speed. of said propeller, the combination firstregulating means for controlling-the pitch of said, propeller toregulatethe speed of the powerplant, secondregulatingsmcans including a deviceresponsive to an. operating temperature of thepowerplant varying withthe speed of said gas turbine and air compressor for controlling thepressure differential across said gas turbine to maintain? saidtemperature substantially at a selected value, means for varying thedatum of said first and second regulating means, a control memberoperatively connected toactuate saidV datum varying means to selectvarious values of saidpowerplant speed andv temperature, additionalcontrol means for varying the datum of Vsaid second regulating meanswithout alteringthe datum of. the. first, regulating means.

5.v In a temperature and` speed control system for aninternal,combustionpowerplant drivingja power shaft and including, inseries ow relation, an air compressor, a

combustion chamber and a gas turbine connected to drive said compressor;the combination with variable exhaust opening means for controlling saidgas turbine, of a mechanism for varying said opening means, firstregulating Vmeans connected to said mechanism and responsive to avpoWerplant-temperature condition dependent upon the adjustment of saidvariable exhaust opening means for actuating said mechanism to maintainthe powerplant at a selected temperature, second regulating meansincluding speed governing means sensing variations in the.

speed of said power shaft for regulating the load applied thereto, andcommon control means operatively connected with said rst and secondregulating means for varying the datum thereof.

6. In a speed and temperature control system for an aircraft enginedriving avariable pitch propeller and including in series flow relationan air compressor, a combustionV chamber and a gas turbine connected todrive said compressor, the combination comprising an adjustableengine-driven governor for controlling the blade angle of the propellerto maintain the propeller speed at the selected value, a servomechanismfor controlling the speed of said gas turbine, servo controlmeans for con-` trolling said servo mechanism, a plurality of sensordevices. operatively connected to actuate said servo control meansincluding means responsive to an operating engine temperature resultingfrom combustion for regulating the turbine speed to maintain said enginetemperature substantially at a selected value, means responsive tothecompressor discharge pressure operatively connected with saidtemperature responsive means for varyingthe effect thereof to modifysaid engine temperature as a predetermined function of compressor`discharge pressure, means responsive to variations of surrounding airtemperature operatively connected to said first mentioned temperatureresponsive means for altering the effect thereof vtomodify said enginetemperature as a preselected function of said surrounding temperature,common manually operable control means operatively connected to saidgovernor and to said servo mechanism for altering the datum of saidgovernor and servo mechanism to select various combinations of propellerspeed and said engine operating temperature according to a predeterminedschedule, and additional control means operating upon saidv ser-vomechanism for altering said speed-temperature schedule without varyingthe propeller speed;

7. ln a speed and temperature control system for an internal combustionengine including ay turbo-compressor and driving a power shaft subjectto a controllable load, the combination with an adjustable engine-drivengovernor for regulating the load on the power shaft to main-V tain theshaft speed at a selected value, of a servomechanism for controlling thespeed of the turbocompressor, means responsive to an operatingtemperature of the engine which varies with the speed of theturbo-compressor, an operative connection for actuating said servomechanism from said temperature responsive means to regulate the speedof the turbo-compressor sov as to maintain said engine temperaturesubstantially at a selectedv value, common control means for varying thedatum of said governor and the datum of said servo mechanism to modifythe shaft speed and said engine temperature so as to produce variouscombinations of said speed and temperature according to a predeterminedschedule, and means responsive to changes of surrounding air pressureand temperature operatively. connected with said servo mechanism foraltering the effect of said engine temperature responsive means tomodify said engine temperature as a preselected function of saidsurrounding air pressure and temperature..

8. In a speed and temperature control system for an internal combustionengine driving a power shaft subject to a controllable load andincluding in series flow relation an air compressor, a combustionchamber and a gas turbine for driving said compressor, the combinationwith a speed governor for regulating the load on said power shaft tocontrol the shaft speed, of a servo mechanism for regulating the supplyof actuating gas to said gas turbine, means responsive to an engineoperating ternperature resulting from combustion for actuating saidservo mechanism to maintain said engine temperature substantially at aselected value, a common manually operable control member for varyingthe datum of both said governor and servo mechanism to select variousvalues of shaft speed and engine temperature in accordance with thesetting of said control member, and additional control means for varyingthe datum of said servo mechanism to change the engine temperatureobtainable for a given setting of said control member without alteringthe shaft speed.

9. For use with an internal combustion engine driving a power membersubject to controllable load and having in series ow relation an aircompressor, a combustion chamber and a gas turbine driving saidcompressor, a speed and temperature control system including anadjustable governor responsive to the speed of said power member forregulating the load on said member to control the speed thereof, aregulating device for controlling the supply of actuating gas to saidturbine, means responsive to an operative temperature of the engineresulting from combustion for controlling said regulating device to keepsaid temperature substantially at a selected value, a common controlmember for varying the datum of said governor and altering the operativesetting of said temperature responsive means to select various values ofsaid speed and temperature, and additional means responsive tovariations of surrounding temperature for altering the operative settingof the rst mentioned temperature responsive means as a preselectedfunction of the surrounding air temperature.

10. In a speed and temperature control system for an internal combustionengine driving a power member under controllable load and having inseries ilow relation an aix. compressor, a combustion chamber and a gasturbine driving said compressor, the combination with a lgovernorresponsive to the speed of said power member -for regulating the load onsaid power member to control the speed thereof, of a turbine regulatorfor varying the supply of actuating gas to said gas turbine, meansresponsive to an operating temperature of the engine varying with thesupply of said actuating substance to the turbine, an operativeconnection for actuating said turbine regulator from said temperatureresponsive means to keep said temperature substantially at a selectedvalue, a common control member for varying the datum of said governorand the operative setting of said temperature responsive means to selectvarious values of said speed and temperature, and additional meansresponsive to surrounding air pressure variations for altering theoperative setting of said temperature responsive means in predeterminedrelation to said air pressure.

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